Turning bar fulcrum for electric motors



March 24; 1959 H. o. KOONS 7 2,879,414

TURNING BAR FULCRUM FOR ELECTRIC MOTORS ,Filed Jan. 16, 1956 INVENTOR. HAROLD O. KOONS p, Y ..J

ATTORNEY ited ates Pa TURNING BAR FUL'CRUM FOR ELECTRIC MOTORS Harold O. Koons, Willoughby, Ohio, Electric Products Co., Cleveland, of Ohio assignor to The Ohio, a corporation This invention relates to the art of electric motors, and more particularly to an improved means for manually turning the armature of an electric motor.

The invention is particularly applicable to synchronous motors and will be described with particular reference thereto, although it will be appreciated that the invention is not so limited.

In the art of synchronous motors and particularly in the original installation of such synchronous motors or in making adjustments on the machinery driven by the motor, it is often necessary to rotate the motor through small arcs of rotation varying anything from a few degrees to several complete revolutions. It is quite impractical to effect these small movements by electrically energizing the motor; thus various expedients have grown up in the past to assist in this problem. One such expedient is disclosed in US. Patent 909,216 where hydraulic means are used to move a piston supported lever against a toothed wheel. Such an installation is expensive. Another more common method is the use of a turning bar. Sockets are provided in the rim of the armature to receive the end of the turning bar. A temporary fulcrum is built by the operator from any rigid materials conveniently at hand, e.g., bricks. The turning bar is then inserted in one of the sockets and using the bricks as a fulcrum, the rotor of the motor can be adjusted in as small increments as desired with the operator having complete control of the adjustment at all times. Another difiiculty with such a temporary fulcrum is that if the operator should advance the rotor beyond the desired point, it is impossible for him to return it without building another temporary fulcrum on the diametrically opposite side of the motor. Furthermore, when the adjustments are completed, it is necessary for the operator to remove the temporary fulcrum and clean up the mess usually left by the materials employed.

The present invention contemplates a turning bar fulcrum which obviates the necessity for constructing a makeshift fulcrum of miscellany for the starting operation with the attendant need to remove it thereafter.

In accordance with the present invention, there is provided a turning bar fulcrum for an electric motor comprising a bar rest spaced from and substantially opposite the rim of the armature and on a radial line through the shaft of said armature, and means affixed to the stator for rigidly supporting said bar rest.

A principal object of the invention is the provision of an improved turning bar fulcrum which overcomes the difiiculties and objections of the prior art.

Another object of this invention is the provision of a simplified means for manually turning heavy armatures through small arcs of rotation, particularly in the case of synchronous motors, whereby make-shift structures are eliminated and the safety of operation is improved.

Still another object of the invention is the provision of a new and improved turning bar fulcrum which is attractive in appearance, which is safe and rugged in construction, which can be an integral part of the motor and which enables the motor to be rotated in either direction through any desired arc.

The invention may take physical form in certain ar rangements and combination of parts, a preferred embodiment of which is described in detail herein and illustrated in the accompanying drawing wherein:

Figure 1 is a fragmentary front elevational view of a synchronous motor having mounted thereon a turning bar fulcrum embodying the present invention.

Figure 2 is a fragmentary top cross-sectional view of Figure 1.

Figure 3 is a fragmentary side elevational view of Figure 1.

Referring more particularly to Figure 1, this is a fragmentary view in an axial direction of a synchronous motor having a stator generally indicated at 1 and an armature generally indicated at 2 mounted on a shaft 3. As is the customary practice with armatures in motors of this type, there is provided a rim 4 to which are attached a plurality of coils 5. The rim 4 may be provided with indentations or sockets 6, such provision being common in the large diameter motors and/ or generators.

Opposite the rim 4 and spaced therefrom is a bar rest 7 which may desirably have one or more indentations 8 adapted to cradle a turning bar and prevent lateral movement thereof.

Means for supporting the bar rest 7 are attached directly to the stator 1 and, in the embodiment shown in the annexed drawings, desirably comprise a pair of J shaped members 9 and 10 intersecting at right angles beneath the bar rest 7 and supporting the latter in a fixed position. The loop ends of said members 9 and 10 are suitably flanged at 11 and 12 respectively and secured by suitable means, e.g., bolts 13 and 14 respectively to the stator 1.

In Figures 2 and 3 a turning bar 15 is shown in the position where it is useful in rotating the armature 2 by engaging one of the plural sockets 6 in the rim 4. Application of force to the free end of the bar 15 will cause the armature 2 to rotate in a clock-wise direction.

For most purposes, the bar rest 7 is located opposite the rim and spaced therefrom and also in substantially the same horizontal plane as the center of the shaft of the armature. Of course, as departure from the horizontal plane is increased, it becomes more ditlicult to operate the fulcrum and promote rotation of the armature.

A bar rest 16 having indentations 17 on its lower surface is mounted in the intersection of the members 9 and 10 whereby the turning bar 15 may be employed to rotate the armature in the opposite direction if desired.

Thus, with the device shown in Figures 1, 2 and 3, there has been provided a turning bar fulcrum rigidly attached to the stator of a large electric motor or generator which facilitates an operation normally associated with such equipment, i.e., rotating the armature through desired small increments for the purpose of aligning the motor with its associated driven apparatus or for the purpose of making adjustments on such apparatus. Moreover, this improved fulcrum enables cleaning, repair and adjust ment of armature parts more convenient than heretofore and obviates the necessity for constructing temporary and frequently unsafe structures for accomplishing the same purpose.

Other modes of applying the principle of this invention may be employed instead of those specifically set forth above, changes being made as regards the details herein disclosed, provided the elements set forth in the following claim, or the equivalent of such be employed.

Having thus described my invention, I claim:

In combination with an electric motor having a stator frame provided with a stator end surface and a rotor provided with a rotor end surface having circumferentially spaced sockets around the periphery thereof, the stator closely surrounding the outer surface of said rotor, the provision of a first member rigidly secured to said stator end surface and extending towards the axis of the rotor spaced from said rotor end, a second member rigidly secured to said stator end surface at a distance from said first member and joined to said first member to provide therewith, a bar rest, said bar rest being spaced from said end surfaces and aligned With said sockets, and a fulcrum bar on said rest and extending generally transversely of said end surfaces into one of said sockets whereby fulcrum-like movement of said bar relative to said rest causes rotational movement of the rotor relative to the stator.

References Cited in the file of this patent UNITED STATES PATENTS Hollenbeck July 23, 1889 Cantono Mar. 13, 1900 Kimball Jan. 19, 1904 Pomeroy Jan. 12, 1909 Schmidt Nov. 13, 1945 Kobbe Feb. 22, 1949 Brugmann Dec. 12, 1950 FOREIGN PATENTS Germany Oct. 17, 1942 

